Symposium on Advances in Small Hospital Care
A Military Anti-Shock Trousers Program in the Small Hospital Charles Abernathy, M.D.* T. C. Dickinson, M.D., t and Hamilton Lokey, M.D.t
Military Anti-Shock Trousers (MAST) were first described by Circle in 1903 and further refined as the G-suit used during World War II for dive bomber pilots. When applied to the lower half of the body this pneumatic garment has proved to be effective for control of hemorrhagic shock. 1 There is an almost immediate autotransfusion of approximately one liter of blood into the intravascular volume with the additional advantages of control of intra-abdominal or lower extremity bleeding and stabilization of fractures in that area. In 1977 a MAST trousers program was initiated in the five county mountainous region surrounding Montrose, Colorado. Initially one of the most isolated towns, Norwood, Colorado, which even in good weather is over one hour by ambulance from the nearest hospital, Montrose Memorial Hospital, was identified as a pilot area. The emergency medical technicians in this area were given a two hour course in the use of MAST trousers and were supplied with a pair of trousers for each ambulance. At the same time, the surgeons on the receiving end reviewed the indications and uses of the garment in order to teach the course to ambulance attendants and to be adept in its management once the patient with MAST trousers reached the hospital. The MAST trousers cost approximately $350 per pair and presently can be purchased from one of two manufacturers.§ Their acceptance by emergency medical technicians and physicians of the region was found to be very favorable. To date, no complications secondary to the use of the trousers have occurred and there have been several instances in which the trousers were of unquestionable value. In addition to the well known benefits of the trousers, an even more important aspect has been that it increases the recogniti~m and '''Staff Surgeon, Montrose Memorial Hospital, Montrose, Colorado. tStaff Surgeon, Montrose Memorial Hospital, Montrose, Colorado t Staff Surgeon, Montrose Memorial Hospital, Montrose, Colorado §David Clark Company, Worcester, Massachusetts: MAST Anti-Shock Trousers; Jobst Company, Toledo, Ohio: Three Section Standard Anti-Shock Airpants.
Surgical Clinics of North America -Vol. 59, No. 3, June 1979
461
462
CHARLES ABERNATHY ET AL.
awareness of hemorrhagic shock and makes certain, through the training programs, that patients with major trauma arrive promptly at the nearest categorized trauma facility where a surgeon is capable of removal of the trousers, rather than being delayed at a facility not so categorized. The use of the trousers denoting critical trauma and necessitating a higher categorized level appears to expedite the triage and care of the patient. Emergency medical technicians in this area are not trained in the use of endotracheal intubation but, as identified in the teaching outline below, are well versed in the respiratory and ventilation problems that may occur following application of MAST trousers. In the years prior to their use, much effort was made to train emergency medical technicians in the indications and administration of intravenous fluids. However, in cases of severe hemorrhagic shock almost invariably one of four circumstances would prevail: intravenous administration of fluids was not started in the field; when it was, the needle or catheter was of too small a caliber; the apparatus was extravasated soon after being started and the patient received virtually no fluids; or, if started in the field and the venous line was open, rarely did the patient receive more than 400 or 500 ml of lactated Ringer's solution, regardless of the time of pre-hospital transportation. Therefore, the 1000 ml of whole blood in vivo transfusion which would be accrued from the use of the MAST trousers was considered to be a much more realistic approach to the treatment of severe hemorrhagic shock in the field. · In the critically ill patient, the ambulance personnel frequently place the trousers beneath the patient but do not inflate them without direct communication with either the local physician nearest the site of trauma or permission from the surgeon to whom the patient is being transferred. Two-way radio communication is therefore essential. When direct radio communication is not available to an emergency room which is staffed 24 hours a day by an in-house physician, a phone patch via radio to the referring physician will meet this need. In the two years that MAST trousers have been used in this fivecounty region, the trousers have been placed beneath patients (but not inflated) at the accident scene numerous times when the emergency medical technician personnel were unsure as to the status of the blood loss. The trousers have been inflated on four patients, and in three of these, the hematocrit upon arrival at the hospital was in the low twenties and each patient was critically hypovolemic. In the fourth case the patient did not necessarily benefit from the application of the trousers. Pulmonary edema, hypervolemia, or respiratory depression was not noted in any of the four patients during use of the garment. The MAST concept has been found to be an extremely effective addition to the care of the severely injured patient in an isolated rural setting. It can convert a situation requiring blood transfusion and operative intervention within minutes to a controlled, orderly approach with time, sometimes measured in hours, to mobilize personnel, blood, and equipment in the small community hospital.
A MILITARY ANTI-SHOCK TROUSERS PROGRAM
463
CASE REPORTS Case 1 A 23 year old female mine mechanic was involved in a crushing injury between two ore carts approximately 35 minutes distant from the nearest hospital. The patient was seen briefly and triaged by a local physician who began an intravenous line using lactated Ringer's solution. The patient was then transferred by ground ambulance to the nearest small community hospital, where she was in deep hypovolemic shock with a rapidly expanding abdomen. Two large bore intravenous catheters were immediately inserted. Samples were drawn for type and cross match of multiple units of whole blood, and the MAST trousers put in place, with the legs inflated. The patient's blood pressure went in three minutes from unobtainable to 80 systolic where it remained for approximately 40 minutes while other resuscitation measures such as insertion of a Foley catheter, portable chest x-ray, and a brief medical history were undertaken. With the trousers inflated, the patient was transferred to the operating room with simultaneous transfusion of two units of type-specific whole blood. A laparotomy was performed and repair of the superior mesenteric artery laceration was accomplished. The patient receovered rapidly and was discharged on the seventh postoperative day.
Discussion The above in-hospital use of the MAST concept is an example of the particular benefit it has in a small community hospital setting where a walking blood bank is usually the source of blood. The antishock trousers allow a precious few minutes of extra time for obtaining a sample for type and cross match and for institution of other resuscitative measures when time is a critical factor. The resources of a small hospital can be mobilized, including laboratory, radiology, operating crew, and so on, from their homes since small hospitals seldom have "after hours" crews in the hospital. However, the time from arrival at the small community hospital emergency room to definitive repair in the operating room is comparable to that noted at most metropolitan medical centers. Case 2 A 4 7 year old woman in deep hypovolemic shock was found lying comatose on the floor of her bathroom with the toilet filled with bloody stool. Intravenous administration of fluids was started at the scene by the local physician, and the patient was transported 65 miles by a ground ambulance to the nearest hospital facility, Montrose Memorial Hospital. The response time from the moment the patient was seen to the time of arrival at the emergency room of the hospital was approximately one hour and forty minutes. The patient initially had a blood pressure in the 60 to 80 systolic range, but after one-half hour of ground transportation, the pressure was unobtainable. All three compartments of the MAST trousers were then inflated under the direct supervision of the accompanying physician. The blood pressure rose to 90 systolic and remained there until the ambulance arrived at the emergency room, where blood was typed, cross matched, and administered. Another intravenous line was started through a large bore catheter. The patient was alert with stable vital signs, and each of the three compartments of the trousers was deflated in sequence in the emergency room rather than in the operating room. No loss of pressure or gain in the pulse rate was noted when the trousers were deflated, and the patient was admitted to the Special Care Unit and closely followed. An active duodenal ulcer was demonstrated during an upper gastrointestinal study. No further bleeding occurred and the patient was discharged on the seventh hospital day.
464
CHARLES ABERNATHY ET AL.
Discussion The above is an example of the benefit of the trousers when long pre-hospital travel time and distances are involved. In geographically isolated areas, MAST trousers can be invaluable in preventing or lessening the morbidity and possible mortality of shock. Although the trousers were removed in the emergency room rather than in the operating room in this instance, it was only under the best of controlled circumstances with the operating room crew standing by, and all resources in readiness.
A TEACHING OUTLINE FOR THE USE OF THE MILITARY ANTI-SHOCK TROUSERS':' I. A review and discussion of the criteria and physiology of hypovolemic shock, with emphasis on the use of systolic blood pressure below 90 as a guide to begin thinking of putting the trousers in place (in obvious or potential blood loss situations). The emergency medical technician should begin initial contact with the physician consultant. Begin administration of intravenous fluids as soon as possible. II. Discussion of the historic aspects of Military Anti-Shock Trousers and the criteria for use as well as potential benefits to the patient: Benefits of the trousers (Fig. 1): Two unit whole blood auto-transfusion. Stabilization of pelvic and long bone fractures of the lower extremities. Decrease or stopping of intra-abdominal bleeding ca:used by the surrounding counter pressure around the abdomen. Two illustrative cases in which the trousers might be used: Multiple trauma from an automobile accident with probable bro.ken femur, systolic blood pressure below 90, and an alert patient with no evidence of respiratory depression. Comatose patient from an automobile accident with no obvious external injuries but a blood pressure unobtainable and pulse felt in the inguinal area. Discussion of monitoring of neurologic signs and adequacy of ventilation. III. Pitfalls in the use of Military Anti-Shock Trousers (Fig. 2): A major problem is respiratory embarrassment owing to several factors, including: ''Note: MAST trousers should not be fully inflated on a volunteer during demonstration. A sudden rise in blood volume could cause rupture of preexisting cerebral aneurysms or other injury.
A MILITARY ANTI-SHOCK TROUSERS PROGRAM
465
Figure 1. The therapeutic benefits of the MAST suit include effective autotransfusion of two units of blood, stabilization of fractures of the pelvis and lower extremities, and reduction of intra-abdominal bleeding.
466
CHARLES ABERNATHY ET AL.
Q) Respiratory Embarrassment
®
Increase in Intracranial or Intrathoracic Bleeding
Q) Renewed Bleeding From lacerations Above level of Suit Figure 2. The potential complications of the MAST trousers are demonstrated.
A MILITARY ANTI-SHOCK TROUSERS PROGRAM
467
Potential abuse of the trousers when there is no actual blood loss with creation of hypervolemia and subsequent pulmonary edema. Pressure on the abdomen causing the diaphragm to riseparticularly important in a patient who already has some ventilation problems secondary to previously existing chronic obstructive pulmonary disease or acute problems such as multiple rib fractures. Inflation of the trousers with the subsequent autologous transfusion can cause an increase in already existing intracranial or intrathoracic bleeding. If either the ventilation or the sensorium decreases, the transporting personnel and the physician must determine whether the priorities indicate that the hypovolemic shock takes precedence over intracranial or intrathoracic increase in bleeding. A potential but quite controllable pitfall is increased or renewed bleeding from lacerations above the level of the suit. This, of course, could be interpreted as a !!ign that the patient is being resuscitated from the shock state and the bleeding should be able, in most instances, to be controlled with conventional means (i.e., direct pressure, and so on). IV. Medicolegal aspects of Military Anti-Shock Trousers: The trousers may be placed under virtually any patient at the discretion of the transporting personnel. The trousers should not be inflated (either the legs only or the legs and abdominal portion) without direct verbal communication with a physician. This can be done by a telephone or radio, or a radio with patch to telephone. At least one of the transporting personnel must have attended the Military Anti-Shock Trouser training program. V. Practical demonstration of application of the Military Anti-Shock Trousers: Explanation of the blow-off valves and/or gauges that limit the pressure to 90 mm H •. Note: If trousers are equipped with gauges, pressures of 25 to 30 mm Hg may be tried and theresponse of the patient evaluated. Explanation that it is frequently desirable to inflate only the legs first and see if this causes a response with the elevation of blood pressure. However, it must be remembered that it is only the abdominal portion of the trousers that will give the benefit of decreasing intra-abdominal bleeding.
468
CHARLES
ABERNATHY ET AL.
Care of the trousers is discussed including avoidance of sharp rocks or glass underneath the trousers when they are placed, and cleaning of the trousers. VI. Management by the physician. Trousers should not be removed except in the operating room or other controlled (i.e., blood ready) situations. Must encourage emergency medical technicians to monitor respirations carefully via radio with periodic communication with the physician during transportation to the hospital. In prolonged inflation situations, metabolic acidosis has been noted.
REFERENCES 1. Cutler, B. S., and Daggett, W.: Application of the "G-suit" to the control of hemorrhage in massive trauma. Ann. Surg., 173:511, 1971. Montrose Memorial Hospital 800 South Third Street Montrose, Colorado 81401 CoMMENTARY
]. Cuthbert Owens, M.D.* In 1977 the American College of Surgeons Committee on Trauma made three major revisions in their 1973list of essential equipment for ambulances. They added MAST trousers and two-way ambulance-hospital communication and deleted intravenous fluids. The observations and experiences of the surgeons at this small community hospital in a mountainous region document the reasons for these revisions. Intravenous fluid therapy has not been a part of the required curriculum taught in the basic emergency medical technical course of 81 hours. Neither are there enough time or patients available to adequately train volunteer EMT personnel, much less have them maintain the skill in a small community. Intravenous therapy administered peripherally to a critically ill patient is not always a simple procedure, especially in the field. As stated by the author, problems not only occur with introduction of an adequate intravenous line but also with the amount of fluid administered. In view of these problems, trained ambulance attendants should be capable of treating critical shock by some means other than elevation of the lower limbs and respiratory assistance. The MAST trousers concept supported by medical advice over the radio meets this need in both the urban and rural areas by conserving time and providing the best possible means of shock therapy in an adverse environment. The volunteer ambulance service initially chosen by the Montrose Memorial Hospital staff for use of the MAST trousers averages no more *Professor of Surgery, University of Colorado Medical School, Denver, Colorado
A Military Anti-Shock Trousers Program in the Small Hospital Charles Abernathy, M.D.* T. C. Dickinson, M.D., t and Hamilton Lokey, M.D.t
Military Anti-Shock Trousers (MAST) were first described by Circle in 1903 and further refined as the G-suit used during World War II for dive bomber pilots. When applied to the lower half of the body this pneumatic garment has proved to be effective for control of hemorrhagic shock. 1 There is an almost immediate autotransfusion of approximately one liter of blood into the intravascular volume with the additional advantages of control of intra-abdominal or lower extremity bleeding and stabilization of fractures in that area. In 1977 a MAST trousers program was initiated in the five county mountainous region surrounding Montrose, Colorado. Initially one of the most isolated towns, Norwood, Colorado, which even in good weather is over one hour by ambulance from the nearest hospital, Montrose Memorial Hospital, was identified as a pilot area. The emergency medical technicians in this area were given a two hour course in the use of MAST trousers and were supplied with a pair of trousers for each ambulance. At the same time, the surgeons on the receiving end reviewed the indications and uses of the garment in order to teach the course to ambulance attendants and to be adept in its management once the patient with MAST trousers reached the hospital. The MAST trousers cost approximately $350 per pair and presently can be purchased from one of two manufacturers.§ Their acceptance by emergency medical technicians and physicians of the region was found to be very favorable. To date, no complications secondary to the use of the trousers have occurred and there have been several instances in which the trousers were of unquestionable value. In addition to the well known benefits of the trousers, an even more important aspect has been that it increases the recogniti~m and '''Staff Surgeon, Montrose Memorial Hospital, Montrose, Colorado. tStaff Surgeon, Montrose Memorial Hospital, Montrose, Colorado t Staff Surgeon, Montrose Memorial Hospital, Montrose, Colorado §David Clark Company, Worcester, Massachusetts: MAST Anti-Shock Trousers; Jobst Company, Toledo, Ohio: Three Section Standard Anti-Shock Airpants.
Surgical Clinics of North America -Vol. 59, No. 3, June 1979
461
462
CHARLES ABERNATHY ET AL.
awareness of hemorrhagic shock and makes certain, through the training programs, that patients with major trauma arrive promptly at the nearest categorized trauma facility where a surgeon is capable of removal of the trousers, rather than being delayed at a facility not so categorized. The use of the trousers denoting critical trauma and necessitating a higher categorized level appears to expedite the triage and care of the patient. Emergency medical technicians in this area are not trained in the use of endotracheal intubation but, as identified in the teaching outline below, are well versed in the respiratory and ventilation problems that may occur following application of MAST trousers. In the years prior to their use, much effort was made to train emergency medical technicians in the indications and administration of intravenous fluids. However, in cases of severe hemorrhagic shock almost invariably one of four circumstances would prevail: intravenous administration of fluids was not started in the field; when it was, the needle or catheter was of too small a caliber; the apparatus was extravasated soon after being started and the patient received virtually no fluids; or, if started in the field and the venous line was open, rarely did the patient receive more than 400 or 500 ml of lactated Ringer's solution, regardless of the time of pre-hospital transportation. Therefore, the 1000 ml of whole blood in vivo transfusion which would be accrued from the use of the MAST trousers was considered to be a much more realistic approach to the treatment of severe hemorrhagic shock in the field. · In the critically ill patient, the ambulance personnel frequently place the trousers beneath the patient but do not inflate them without direct communication with either the local physician nearest the site of trauma or permission from the surgeon to whom the patient is being transferred. Two-way radio communication is therefore essential. When direct radio communication is not available to an emergency room which is staffed 24 hours a day by an in-house physician, a phone patch via radio to the referring physician will meet this need. In the two years that MAST trousers have been used in this fivecounty region, the trousers have been placed beneath patients (but not inflated) at the accident scene numerous times when the emergency medical technician personnel were unsure as to the status of the blood loss. The trousers have been inflated on four patients, and in three of these, the hematocrit upon arrival at the hospital was in the low twenties and each patient was critically hypovolemic. In the fourth case the patient did not necessarily benefit from the application of the trousers. Pulmonary edema, hypervolemia, or respiratory depression was not noted in any of the four patients during use of the garment. The MAST concept has been found to be an extremely effective addition to the care of the severely injured patient in an isolated rural setting. It can convert a situation requiring blood transfusion and operative intervention within minutes to a controlled, orderly approach with time, sometimes measured in hours, to mobilize personnel, blood, and equipment in the small community hospital.
A MILITARY ANTI-SHOCK TROUSERS PROGRAM
463
CASE REPORTS Case 1 A 23 year old female mine mechanic was involved in a crushing injury between two ore carts approximately 35 minutes distant from the nearest hospital. The patient was seen briefly and triaged by a local physician who began an intravenous line using lactated Ringer's solution. The patient was then transferred by ground ambulance to the nearest small community hospital, where she was in deep hypovolemic shock with a rapidly expanding abdomen. Two large bore intravenous catheters were immediately inserted. Samples were drawn for type and cross match of multiple units of whole blood, and the MAST trousers put in place, with the legs inflated. The patient's blood pressure went in three minutes from unobtainable to 80 systolic where it remained for approximately 40 minutes while other resuscitation measures such as insertion of a Foley catheter, portable chest x-ray, and a brief medical history were undertaken. With the trousers inflated, the patient was transferred to the operating room with simultaneous transfusion of two units of type-specific whole blood. A laparotomy was performed and repair of the superior mesenteric artery laceration was accomplished. The patient receovered rapidly and was discharged on the seventh postoperative day.
Discussion The above in-hospital use of the MAST concept is an example of the particular benefit it has in a small community hospital setting where a walking blood bank is usually the source of blood. The antishock trousers allow a precious few minutes of extra time for obtaining a sample for type and cross match and for institution of other resuscitative measures when time is a critical factor. The resources of a small hospital can be mobilized, including laboratory, radiology, operating crew, and so on, from their homes since small hospitals seldom have "after hours" crews in the hospital. However, the time from arrival at the small community hospital emergency room to definitive repair in the operating room is comparable to that noted at most metropolitan medical centers. Case 2 A 4 7 year old woman in deep hypovolemic shock was found lying comatose on the floor of her bathroom with the toilet filled with bloody stool. Intravenous administration of fluids was started at the scene by the local physician, and the patient was transported 65 miles by a ground ambulance to the nearest hospital facility, Montrose Memorial Hospital. The response time from the moment the patient was seen to the time of arrival at the emergency room of the hospital was approximately one hour and forty minutes. The patient initially had a blood pressure in the 60 to 80 systolic range, but after one-half hour of ground transportation, the pressure was unobtainable. All three compartments of the MAST trousers were then inflated under the direct supervision of the accompanying physician. The blood pressure rose to 90 systolic and remained there until the ambulance arrived at the emergency room, where blood was typed, cross matched, and administered. Another intravenous line was started through a large bore catheter. The patient was alert with stable vital signs, and each of the three compartments of the trousers was deflated in sequence in the emergency room rather than in the operating room. No loss of pressure or gain in the pulse rate was noted when the trousers were deflated, and the patient was admitted to the Special Care Unit and closely followed. An active duodenal ulcer was demonstrated during an upper gastrointestinal study. No further bleeding occurred and the patient was discharged on the seventh hospital day.
464
CHARLES ABERNATHY ET AL.
Discussion The above is an example of the benefit of the trousers when long pre-hospital travel time and distances are involved. In geographically isolated areas, MAST trousers can be invaluable in preventing or lessening the morbidity and possible mortality of shock. Although the trousers were removed in the emergency room rather than in the operating room in this instance, it was only under the best of controlled circumstances with the operating room crew standing by, and all resources in readiness.
A TEACHING OUTLINE FOR THE USE OF THE MILITARY ANTI-SHOCK TROUSERS':' I. A review and discussion of the criteria and physiology of hypovolemic shock, with emphasis on the use of systolic blood pressure below 90 as a guide to begin thinking of putting the trousers in place (in obvious or potential blood loss situations). The emergency medical technician should begin initial contact with the physician consultant. Begin administration of intravenous fluids as soon as possible. II. Discussion of the historic aspects of Military Anti-Shock Trousers and the criteria for use as well as potential benefits to the patient: Benefits of the trousers (Fig. 1): Two unit whole blood auto-transfusion. Stabilization of pelvic and long bone fractures of the lower extremities. Decrease or stopping of intra-abdominal bleeding ca:used by the surrounding counter pressure around the abdomen. Two illustrative cases in which the trousers might be used: Multiple trauma from an automobile accident with probable bro.ken femur, systolic blood pressure below 90, and an alert patient with no evidence of respiratory depression. Comatose patient from an automobile accident with no obvious external injuries but a blood pressure unobtainable and pulse felt in the inguinal area. Discussion of monitoring of neurologic signs and adequacy of ventilation. III. Pitfalls in the use of Military Anti-Shock Trousers (Fig. 2): A major problem is respiratory embarrassment owing to several factors, including: ''Note: MAST trousers should not be fully inflated on a volunteer during demonstration. A sudden rise in blood volume could cause rupture of preexisting cerebral aneurysms or other injury.
A MILITARY ANTI-SHOCK TROUSERS PROGRAM
465
Figure 1. The therapeutic benefits of the MAST suit include effective autotransfusion of two units of blood, stabilization of fractures of the pelvis and lower extremities, and reduction of intra-abdominal bleeding.
466
CHARLES ABERNATHY ET AL.
Q) Respiratory Embarrassment
®
Increase in Intracranial or Intrathoracic Bleeding
Q) Renewed Bleeding From lacerations Above level of Suit Figure 2. The potential complications of the MAST trousers are demonstrated.
A MILITARY ANTI-SHOCK TROUSERS PROGRAM
467
Potential abuse of the trousers when there is no actual blood loss with creation of hypervolemia and subsequent pulmonary edema. Pressure on the abdomen causing the diaphragm to riseparticularly important in a patient who already has some ventilation problems secondary to previously existing chronic obstructive pulmonary disease or acute problems such as multiple rib fractures. Inflation of the trousers with the subsequent autologous transfusion can cause an increase in already existing intracranial or intrathoracic bleeding. If either the ventilation or the sensorium decreases, the transporting personnel and the physician must determine whether the priorities indicate that the hypovolemic shock takes precedence over intracranial or intrathoracic increase in bleeding. A potential but quite controllable pitfall is increased or renewed bleeding from lacerations above the level of the suit. This, of course, could be interpreted as a !!ign that the patient is being resuscitated from the shock state and the bleeding should be able, in most instances, to be controlled with conventional means (i.e., direct pressure, and so on). IV. Medicolegal aspects of Military Anti-Shock Trousers: The trousers may be placed under virtually any patient at the discretion of the transporting personnel. The trousers should not be inflated (either the legs only or the legs and abdominal portion) without direct verbal communication with a physician. This can be done by a telephone or radio, or a radio with patch to telephone. At least one of the transporting personnel must have attended the Military Anti-Shock Trouser training program. V. Practical demonstration of application of the Military Anti-Shock Trousers: Explanation of the blow-off valves and/or gauges that limit the pressure to 90 mm H •. Note: If trousers are equipped with gauges, pressures of 25 to 30 mm Hg may be tried and theresponse of the patient evaluated. Explanation that it is frequently desirable to inflate only the legs first and see if this causes a response with the elevation of blood pressure. However, it must be remembered that it is only the abdominal portion of the trousers that will give the benefit of decreasing intra-abdominal bleeding.
468
CHARLES
ABERNATHY ET AL.
Care of the trousers is discussed including avoidance of sharp rocks or glass underneath the trousers when they are placed, and cleaning of the trousers. VI. Management by the physician. Trousers should not be removed except in the operating room or other controlled (i.e., blood ready) situations. Must encourage emergency medical technicians to monitor respirations carefully via radio with periodic communication with the physician during transportation to the hospital. In prolonged inflation situations, metabolic acidosis has been noted.
REFERENCES 1. Cutler, B. S., and Daggett, W.: Application of the "G-suit" to the control of hemorrhage in massive trauma. Ann. Surg., 173:511, 1971. Montrose Memorial Hospital 800 South Third Street Montrose, Colorado 81401 CoMMENTARY
]. Cuthbert Owens, M.D.* In 1977 the American College of Surgeons Committee on Trauma made three major revisions in their 1973list of essential equipment for ambulances. They added MAST trousers and two-way ambulance-hospital communication and deleted intravenous fluids. The observations and experiences of the surgeons at this small community hospital in a mountainous region document the reasons for these revisions. Intravenous fluid therapy has not been a part of the required curriculum taught in the basic emergency medical technical course of 81 hours. Neither are there enough time or patients available to adequately train volunteer EMT personnel, much less have them maintain the skill in a small community. Intravenous therapy administered peripherally to a critically ill patient is not always a simple procedure, especially in the field. As stated by the author, problems not only occur with introduction of an adequate intravenous line but also with the amount of fluid administered. In view of these problems, trained ambulance attendants should be capable of treating critical shock by some means other than elevation of the lower limbs and respiratory assistance. The MAST trousers concept supported by medical advice over the radio meets this need in both the urban and rural areas by conserving time and providing the best possible means of shock therapy in an adverse environment. The volunteer ambulance service initially chosen by the Montrose Memorial Hospital staff for use of the MAST trousers averages no more *Professor of Surgery, University of Colorado Medical School, Denver, Colorado
